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McMenamin S.K.,University of Washington | Bain E.J.,University of Washington | McCann A.E.,University of Washington | Patterson L.B.,University of Washington | And 7 more authors.
Science | Year: 2014

Pigment patterns are useful for elucidating fundamental mechanisms of pattern formation and how these mechanisms evolve. In zebrafish, several pigment cell classes interact to generate stripes, yet the developmental requirements and origins of these cells remain poorly understood Using zebrafish and a related species we identified roles for thyroid hormone (TH) in pigment cell development and patterning, and in postembryonic development more generally We show that adult pigment cells arise from distinct lineages having distinct requirements for TH and that differential TH dependence can evolve within lineages. Our findings demonstrate critical functions for TH in determining pigment pattern phenotype and highlight the potential for evolutionary diversification at the intersection of developmental and endocrine mechanisms.

News Article | February 15, 2017
Site: www.eurekalert.org

Work on gene therapy is showing significant progress for restoring muscle strength and prolonging lives in dogs with a previously incurable, inherited neuromuscular disease. UW Medicine Institute for Stem Cell and Regenerative Medicine scientists are leading the multi-institutional research effort. The disease arises from a mutation in genes that normally make a protein, called myotubularin, essential for proper muscle function. Puppies with this naturally occurring mutation exhibit several features of babies with the same defective gene. The rare disorder, called myotubular myopathy, or MTM, affects only males. It causes fatal muscle wasting. Both dogs and boys with the disease typically succumb in early life due to breathing difficulties. For decades, researchers have struggled to find suitable treatments for genetic muscle diseases like this one. Four collaborating research groups in the United States and France found a way to safely replace the disease-causing MTM gene with a healthy gene throughout the entire musculature of affected dogs. Their most recent findings were published online this week in Molecular Therapy. Their paper reports that diseased dogs treated with a single infusion of the corrective therapy were indistinguishable from normal animals one year later. "This regenerative technology allowed dogs that otherwise would have perished to complete restoration of normal health," said Dr. Martin K. "Casey" Childers, UW Medicine researcher and physician. Childers is a professor of rehabilitation medicine at the University of Washington School of Medicine and co-director of the Institute for Stem Cell and Regenerative Medicine. Gene therapy holds the promise to treat many inherited diseases. To date, this approach has not been widely translated into treatment of skeletal muscle disorders. "We report here a gene therapy dose-finding study in a large animal model of a severe muscle disease where a single treatment resulted in dramatic rescue," said Childers. The findings demonstrate potential application across a wide range of diseases and broadly translate to human studies. The data supports the development of gene therapy clinical trials for myotubular myopathy, the researchers concluded. UW Medicine researchers David Mack, Melissa Goddard, Jessica Snyder, Matthew Elverman, and Valerie Kelly co-authored the report, "Systemic AAV8-mediated gene therapy drives whole-body correction of myotubular myopathy in dogs." This study was conducted in collaboration with Harvard University, Medical College of Wisconsin, Virginia Tech, INSERM, and Genethon.

News Article | December 15, 2016
Site: www.eurekalert.org

Depending on the genetic test given, the altered genes detected and cancer drugs recommended can vary widely for the same cancer patients A preliminary study comparing two commercially available, next-generation genetic sequencing tests in the same cancer patients shows results can differ widely. The findings are reported Dec. 15 in JAMA Oncology. Genetic testing is used in thousands of cancer patients each year. Clinical testing for cancer-associated genetic alterations is growing because of the need to better match cancer patients with effective therapies, the authors note. They explained that tests are done to target drug selection to tumor characteristics. Test reports also sometimes pull up research trials in which the patient might consider participating. However, according to the researchers, little information is available about how closely the output of various sequencing assays match up for an individual's case. The research was led by Dr. Tony Blau, a faculty member in the Department of Medicine at the University of Washington School of Medicine, and investigators at the UW Medicine Center for Cancer Innovation. Blau is also with the UW Medicine Institute for Stem Cell and Regenerative Medicine Research. In their study, nine patients from a community cancer-care practice received reports from two testing platforms: FoundationOne, from FoundationMedicine, and The Guardant360, from Guardant Health. FoundationOne tests tumor samples to characterize 315 cancer-associated genes and 28 other genes prone to rearrangement. The Guardant360 takes blood samples to examine the cell-free DNA that dying tumor cells release into the bloodstream of cancer patients. It sequences 70 genes. In one patient, neither test found any genetic alterations. The remaining patients as a group had 45 alterations, just 10 of which (22 percent) were discovered by both platforms. For two patients, no results matched between the two reports. The test reports of 8 patients with identified alterations mentioned a total of 36 possible treatment drugs. Only 9 drugs were called out by both tests for the same patients. For 5 patients, there was no overlap between the suggested drugs. "Our findings indicate that the output from genetic testing can differ markedly depending on which test is applied," the researchers noted. Because both types of test are performed annually on many cancer patients, they added, the findings are clinically relevant. The FoundationOne test may be detecting a broader range of aberrations than the Guardant360, but the researchers think the discordance between the two tests stems from other causes. The researchers pointed to at least two other studies with similar observations, including one based only on tumor tissue-sampling and another that compared blood and tumor testing. To improve the clinical usefulness of next-generation sequencing tests for cancer treatment, the researchers point to a need for more in-depth comparisons of test results across larger numbers of patients. SouthSound CARE and the Chan Soon-Shiong Family Foundation funded this study. Other institutions participating included Northwest Medical Specialties in Puyallup, Wash., and the Fred Hutchinson Institute for Cancer Outcomes Research.

Kuppusamy K.T.,Institute for Stem Cell and Regenerative Medicine | Kuppusamy K.T.,University of Washington | Jones D.C.,University of Washington | Sperber H.,Institute for Stem Cell and Regenerative Medicine | And 22 more authors.
Proceedings of the National Academy of Sciences of the United States of America | Year: 2015

In metazoans, transition from fetal to adult heart is accompanied by a switch in energy metabolism-glycolysis to fatty acid oxidation. The molecular factors regulating this metabolic switch remain largely unexplored. We first demonstrate that the molecular signatures in 1-year (y) matured human embryonic stem cell-derived cardiomyocytes (hESC-CMs) are similar to those seen in in vivo-derived mature cardiac tissues, thus making them an excellent model to study human cardiac maturation. We further show that let-7 is the most highly up-regulated microRNA (miRNA) family during in vitro human cardiac maturation. Gain- and loss-of-function analyses of let-7g in hESC-CMs demonstrate it is both required and sufficient for maturation, but not for early differentiation of CMs. Overexpression of let-7 family members in hESC-CMs enhances cell size, sarcomere length, force of contraction, and respiratory capacity. Interestingly, large-scale expression data, target analysis, and metabolic flux assays suggest this let-7-driven CM maturation could be a result of down-regulation of the phosphoinositide 3 kinase (PI3K)/AKT protein kinase/insulin pathway and an up-regulation of fatty acid metabolism. These results indicate let-7 is an important mediator in augmenting metabolic energetics in maturing CMs. Promoting maturation of hESC-CMs with let-7 overexpression will be highly significant for basic and applied research. © 2015, National Academy of Sciences. All rights reserved.

Sekeres M.A.,Cleveland Clinic | Kantarjian H.,University of Texas M. D. Anderson Cancer Center | Fenaux P.,Hematology Clinic Service | Becker P.,Institute for Stem Cell and Regenerative Medicine | And 6 more authors.
Cancer | Year: 2011

BACKGROUND: Romiplostim is a peptibody protein that augments thrombopoiesis by activating the thrombopoietin receptor. METHODS: In this phase 2, multicenter, open-label study, 28 thrombocytopenic patients with lower risk myelodysplastic syndromes (MDS) were assigned to receive romiplostim 750 lg administered subcutaneously either weekly or biweekly or administered as biweekly intravenous injections for 8 weeks. Patients also could enter a 1-year study extension phase. RESULTS: At least 1 adverse event was observed in 93% of patients. The most common adverse events were fatigue and headache (18% for both, and 5 events were grade 3 or 4. There was 1 serious treatment-related adverse event in the biweekly intravenous cohort (hypersensitivity). This hypersensitivity resolved without discontinuation of study treatment. No patients developed neutralizing antibodies or bone marrow fibrosis. Of the patients who completed 8 weeks of treatment, 57% had a complete platelet response, an additional 8% had a major platelet response, and 61% did not require a platelet transfusion during this period.Weekly subcutaneous injections achieved the highest mean trough concentrations. CONCLUSIONS: The safety and efficacy profiles of romiplostim in this study suggested that weekly subcutaneous administration of 750 μg romiplostim is an appropriate starting dose for future clinical studies in patients with MDS and thrombocytopenia. © 2010 American Cancer Society.

News Article | November 16, 2015
Site: phys.org

The recent findings should improve scientists' ability to use embryonic stem cells to grow new tissues and organs to replace those damaged by disease or injury. The findings also could lead to new treatments for common disorders ranging from infertility to cancer. The researchers reported on their study in the Nov. 16 issue of the journal Nature Cell Biology. After fertilization, a human egg begins to travel down the fallopian tube. As it does, it begins to divide to form a ball of embryonic cells. Each of these cells, called naive, pre-implantation embryonic cells, has the capacity to develop into any cell type in the human body, an ability called pluripotency. When the developing embryo enters the uterus, it must implant into the uterine lining if the pregnancy is to proceed. When this occurs, the naive stem cells undergo a critical change as they take the first step toward differentiating into specific cell types, such as gut, muscle or nerve cells. Such cells are called primed embryonic stem cells. "Implantation to mother's uterus is arguably one of the hardest things we ever have to do in life," said Ruohola-Baker, University of Washington professor of biochemistry and associate director of the UW Institute for Stem Cell and Regenerative Medicine, who led the research team. "In fact, most embryos fail to successfully implant and the pregnancy ends." Scientists in the field of tissue regeneration are particularly interested this shift. Although primed, post-implantation embryonic stem cells can still turn into any type of human cell, they are more difficult to work with than the pre-implantation, naive cells. To find out more about the differences between naive and primed pluripotent cells, the UW researchers first compared their gene expression profiles. This work, conducted by Yuliang Wang, now a senior research associate at Oregon Health & Science University, uncovered intriguing differences involving genes that affect the cells' metabolism. "The expression of the metabolic genes, particularly those related to the function of mitochondria, was much higher in the naive cells," Wang said. "There was also a big difference in gene expression of a specific enzyme called nicotinamide N-methyltransferase." To determine the effect of these changes, Henrik Sperber, a graduate student in the Ruohola-Baker laboratory, used a technique called mass spectroscopy to compare levels within cells of the metabolites. The approach, called metabolomic analysis, provides a 'chemical snapshot' that pictures in great detail what is going on within cells at a specific stage. Just by looking at the cells metabolomic profiles, researchers saw it was possible to distinguish between naive and primed pluripotent cells. The telltale metabolite that was found to be enriched in naive cells was methylnicotinamide, abbreviated MNA, a product of the metabolic enzyme whose levels increase in many cancers—nicotinamide N-methyltransferase, abbreviated NNMT. When active, NNMT consumes a methyl group from a compound called S-adenosyl methionine. This methyl group is normally used in a gene regulation process called epigenetic histone methylation. Without an adequate supply of the S-adenosyl methionine, regulation by histone methylation—and therefore correct gene expression—cannot take place. The researchers found that in the naive cells NNMT was active and behaved as a metabolic 'methyl-sink' by lowering the level of methyl groups available. It thereby limited gene repression by epigenetic histone methylation. In the primed cells, on the other hand, NNMT activity was low. As a result, S-adenosyl methionine was available for these epigenetic modifications that are required for a cell to enter the primed state. In fact, by knocking out specific genes through CRISPR gene-editing technology, Julie Mathieu, acting instructor in Ruohola-Baker laboratory, demonstrated that it was possible to stabilize the cells in either the primed or naive state by manipulating NNMT activity alone. "Our findings indicate that metabolites alone appear to be able drive many of the key changes in cellular function and differentiation," Ruohola-Baker said. "In addition to advancing our understanding of human embryonic development, the findings suggest we may be able to use metabolites, relatively simple compounds, to alter cell fate in the treatment of common disorders." For example, such an approach might eventually form the basis for treating the most common cause of infertility—the failure of the embryo to successfully implant—or for affecting the cellular changes that lead to the development of cancer. Explore further: New cell line should accelerate embryonic stem cell research More information: The metabolome regulates the epigenetic landscape during naïve-to-primed human embryonic stem cell transition, Nature Cell Biology, DOI: 10.1038/ncb3264

Palpant N.J.,Institute for Stem Cell and Regenerative Medicine | Dudzinski D.,University of Washington
Gene Therapy | Year: 2013

Genetic engineering has emerged as a powerful mechanism for understanding biological systems and a potential approach for redressing congenital disease. Alongside, the emergence of these technologies in recent decades has risen the complementary analysis of the ethical implications of genetic engineering techniques and applications. Although viral-mediated approaches have dominated initial efforts in gene transfer (GT) methods, an emerging technology involving engineered restriction enzymes known as zinc finger nucleases (ZFNs) has become a powerful new methodology for gene editing. Given the advantages provided by ZFNs for more specific and diverse approaches in gene editing for basic science and clinical applications, we discuss how ZFN research can address some of the ethical and scientific questions that have been posed for other GT techniques. This is of particular importance, given the momentum currently behind ZFNs in moving into phase I clinical trials. This study provides a historical account of the origins of ZFN technology, an analysis of current techniques and applications, and an examination of the ethical issues applicable to translational ZFN genetic engineering in early phase clinical trials. © 2013 Macmillan Publishers Limited All rights reserved.

Rickard A.M.,Institute for Stem Cell and Regenerative Medicine | Petek L.M.,Institute for Stem Cell and Regenerative Medicine | Miller D.G.,Institute for Stem Cell and Regenerative Medicine | Miller D.G.,University of Washington
Human Molecular Genetics | Year: 2015

Facioscapulohumeral muscular dystrophy (FSHD) is caused by chromatin relaxation that results in aberrant expression of the transcription factor Double Homeobox 4 (DUX4). DUX4 protein is present in a small subset of FSHD muscle cells, making its detection and analysis of its effects historically difficult. Using a DUX4-activated reporter,we demonstrate the burst expression pattern of endogenous DUX4, its method of signal amplification in the unique shared cytoplasm of the myotube, and FSHD cell death that depends on its activation. Transcriptome analysis of DUX4-expressing cells revealed that DUX4 activation disrupts RNA metabolismincluding RNA splicing, surveillance and transport pathways. Cell signaling, polarity and migration pathways were also disrupted. Thus, DUX4 expression is sufficient for myocyte death, and these findings suggest mechanistic links between DUX4 expression and cell migration, supporting recent descriptions of phenotypic similarities between FSHD and an FSHD-like condition caused by FAT1 mutations. © The Author 2015.

PubMed | University of Washington and Institute for Stem Cell and Regenerative Medicine
Type: | Journal: Advanced drug delivery reviews | Year: 2016

Human pluripotent stem cells (PSCs) represent an attractive source of cardiomyocytes with potential applications including disease modeling, drug discovery and safety screening, and novel cell-based cardiac therapies. Insights from embryology have contributed to the development of efficient, reliable methods capable of generating large quantities of human PSC-cardiomyocytes with cardiac purities ranging up to 90%. However, for human PSCs to meet their full potential, the field must identify methods to generate cardiomyocyte populations that are uniform in subtype (e.g. homogeneous ventricular cardiomyocytes) and have more mature structural and functional properties. For in vivo applications, cardiomyocyte production must be highly scalable and clinical grade, and we will need to overcome challenges including graft cell death, immune rejection, arrhythmogenesis, and tumorigenic potential. Here we discuss the types of human PSCs, commonly used methods to guide their differentiation into cardiomyocytes, the phenotype of the resultant cardiomyocytes, and the remaining obstacles to their successful translation.

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